Definition

Hunger is a feeling experienced usually followed by a desire to eat. In general terms eating (formally ingestion) is the process of consuming Food to provide for the Nutritional needs of an Animal, particularly The often unpleasant feeling originates in the hypothalamus and is released through receptors in the liver. The hypothalamus links the Nervous system to the Endocrine system via the Pituitary gland (hypophysis The liver is a vital organ in the human body and is present in Vertebrates and some other animals Although an average nourished individual can survive weeks without food intake,^[1] the sensation of hunger typically begins after a couple of hours without eating and is generally considered quite uncomfortable. The sensation of hunger can often be alleviated and even mitigated entirely with the consumption of food. Food is any substance usually composed primarily of Carbohydrates Fats water and/or Proteins that can be eaten or drunk by an

Kamala Markandaya, the Indian writer, evokes the horror and pain of hunger in personal terms:

For hunger is a curious thing; at first it is with you all the time, waking and sleeping and in your dreams, and your belly cries out insistently, and there is a gnawing and a pain as if your very vitals were being devoured, and you must stop it at any cost and you buy a moment’s respite even while you know and fear the sequel. Then the pain is no longer sharp but dull, and this too is with you always, so that you think of food many times a day and each time a terrible sickness assails you, and because you know this you try to avoid the thought, but you cannot, it is with you. Then that too is gone, all pain, all desire, only a great emptiness is left , like the sky like a well in drought, and it is now that the strength drains from your limbs and you try to rise and find you cannot, or to swallow water and your throat is powerless, and both the swallow and the effort of retaining the liquid tax you to the uttermost.

– Kamala Markandaya

Hunger pains

When hunger contractions occur in the stomach, these are called hunger pangs. In Human anatomy, the stomach is a J-shaped hollow muscular organ of the Gastrointestinal tract involved in the second phase of Digestion, following Hunger pangs usually do not begin until 12 to 24 hours after the last ingestion of food, in starvation. Starvation (also called inanition) is a severe reduction in Vitamin, Nutrient, and Energy intake and is the most extreme form of A single hunger contraction lasts about 30 seconds, and pangs continue for around 30-45 minutes, then hunger subsides for around 30-150 minutes. ^[2] Individual contractions are separated at first, but are almost continuous after a certain amount of time. ^[2] Emotional states (anger, joy etc. An emotion is a mental and physiological state associated with a wide variety of feelings thoughts and behaviours ) may inhibit hunger contractions. ^[2] Levels of hunger are increased by lower blood sugar levels, and are higher in diabetics. Blood sugar, used in a physiological context is a misnomer and misleading Diabetes mellitus (ˌdaɪəˈbiːtiːz or /ˌdaɪəˈbiːtəs/ /məˈlaɪtəs/ or /ˈmɛlətəs/ often referred to simply as diabetes ( Ancient Greek: grc ^[2] They reach their greatest intensity in 3 to 4 days and may weaken in the succeeding days, though hunger never disappears. ^[3] Hunger contractions are most intense in young, healthy people who have high degrees of gastrointestinal tonus. Periods between contractions increase with old age. ^[2]

Biological mechanisms

The fluctuation of leptin and ghrelin hormone levels results in the motivation of an organism to consume food. Leptin (Greek leptos meaning thin is a 16 kDa Ghrelin is a Hormone produced mainly by P/D1 cells lining the fundus of the human Stomach and epsilon cells of the Pancreas that stimulates Motivation is the reason or reasons for engaging in a particular behavior especially Human behavior as studied in Philosophy, Conflict, Economics When an organism eats, adipocytes trigger the release of leptin into the body. Adipocytes are the cells that primarily compose Adipose tissue, specialized in storing energy as Fat. Increasing levels of leptin results in a reduction of one's motivation to eat. ^[4] After hours of non-consumption, leptin levels drop significantly. These low levels of leptin cause the release of secondary hormone, ghrelin, which in turn reinitiates the feeling of hunger. Ghrelin is a Hormone produced mainly by P/D1 cells lining the fundus of the human Stomach and epsilon cells of the Pancreas that stimulates

Some studies have suggested that an increased production of grehlin may enhance desire towards perceptive food cues, while an increase in stress may also influence the hormone's production. ^[5] These findings support why hunger can prevail under stressful situations.

Behavioral response

Hunger appears to increase activity and movement in many animals - for example, an experiment on spiders showed increased activity and predation in starved spiders, resulting in larger weight gain. Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings ^[6] This pattern is seen in many animals, including humans while sleeping. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus ^[7] It even occurs in rats with their cerebral cortex or stomachs completely removed. Rats are various medium sized long-tailed Rodents of the superfamily Muroidea The cerebral cortex is a structure within the Brain that plays a key role in Memory, Attention, perceptual Awareness, Thought, ^[8] Increased activity on hamster wheels occurred when rats were deprived not only of food, but also water or B vitamins such as thiamine^[9] This response may increase the animal's chance of finding food, though it has also been speculated the reaction relieves pressure on the home population. The related term squirrel cage may refer to * a Squirrel cage rotor * a squirrel cage fan or blower The B vitamins are eight water-soluble Vitamins that play important roles in cell Metabolism. For the similarly spelled pyrimidine see Thymine Thiamin or thiamine, also known as Vitamin B1 ^[7]

See also

• Anorectic
• Eating disorder
• Fasting
• Hypoglycemia
• Starvation
• Thirst

References

External links

• United Nation 2007 report
• Action Against Hunger Giving the most basic Human RIght - The right to food
• Intergovernmental Institution for the use of Micro-algae Spirulina against Malnutrition (IIMSAM)
• Fighting hunger and poverty in Ethiopia (Peter Middlebrook)
• Satiety enhancers in food Scientist Live
• e-learning about Food Security and Hunger from FAO